Stub Networks

[cisco_kid]

Can anyone please explain stub networks to me as i cannot grasp them.
I have read & re-read page 374 6th edition only to become more confused.

Thanks.

[rosen]

hey hi,

Networks can be divided into 2 types
1.> stub networks and transit network

with reference to figure 6.9 page 341 edition 6

Transit networks: those networks which have 2 or more exit/entry points.

eg. check out corp router which has interfaces connected to remote router's 1, 2 and 3. so like any packet coming to the corp router may exit from any of the interfaces which are up.( the exit interface will be decide by the routing table off course)

stub network: this type of networks are the one which have jus one exit point.
eg. look at the wireless router 871 it jus has one connection to remote 3
hence all outgoing traffic by default will have to pass through the gateway 10.1.11.0 which connects it to the remote3 router.
are u thinking why is it so ??
well that's simply because no matter what ever be the destination of the packet created by a host connected to the wireless router ( be it destined to a network connected to remote 1 or remote 2 or remote 3 router ) it will always pass through the 10.1.11.0 link. coz that's the only exit point the wireless router has.

so its as good as no need to check the destination of the packet as there is only one exit point jus make it a default route and go on forwarding packets to it.


well hope i did not confuse u more !!!!

ping me back in case of any probs ?? :confused:

[rosen]

Hi, the routers remote1 and remote 2 in case they have to route a packet to the networks other than networks to which they are directly connected will always hv 2 route the packets through the corp router !! Agreed but check out router remote 3 it can route to the network connected to wireless router directly. Right!! coz its the transit network for the wireless router . . Now that its a transit n/w how can it be a stub. . As for the dual links on r1 they ultimately end up on the same place ie corp router.
At one time only one link will be active, i guess during the static configuration lammle talks abt it . . Hey its already midnight so c Ya 2mro..

well hope its a lot more clear now.i'll try to throw in a bit more light in case it is not.

[Fuzz]

A stub network is one that only has one route in and out. So if you're trying to reach a remote network, all packets must be routed through that interface, regardless of destination network address. So a default route is handy here as one command will send all remote traffic to the correct place i.e the only place it can go.

[dae26]

I keep reading that a stub network only has 1 exit path. Page 374 explains that it is "those [networks] with only one exit path out of the network". Remote1 has two exit paths out of the network, 10.1.2.0 and 3.0. Is the reason it's considered a stub network because both of those paths exit to the same router?

If both of those links are considered one exit path and the router is configured to use the 0.0.0.0 0.0.0.0 wildcard then how does the router know which of the interfaces to throw it out on? 2.0 and 3.0 are both directly connected and would show up in the routing table. Both connected to different interfaces on different subnets but to the same router.

Any explanation or help would be much appreciated.

[Pramod.purohit]

I keep reading that a stub network only has 1 exit path. Page 374 explains that it is "those [networks] with only one exit path out of the network". Remote1 has two exit paths out of the network, 10.1.2.0 and 3.0. Is the reason it's considered a stub network because both of those paths exit to the same router?

If both of those links are considered one exit path and the router is configured to use the 0.0.0.0 0.0.0.0 wildcard then how does the router know which of the interfaces to throw it out on? 2.0 and 3.0 are both directly connected and would show up in the routing table. Both connected to different interfaces on different subnets but to the same router.

Any explanation or help would be much appreciated.


Administrative Distance Dude, We can make one route to act as a backup route by simply increasing the AD value under IP ROUTE command. Now if the main one goes down backup will active. I beleive we can also have both the route active at same time so that router can load balance packets (Not sure weather it works with statice or default routes)

[Fuzz]

Load balancing will work with static routes. If you look at the routing table, you will see two routes listed for the default route.